Drying apparatus



NOV. 6, 1951 ANDREWS 2,574,083

DRYING APPARATUS Filed Dec. 14, 1950 2 SHEETSSHEET l n faweni'oi": 13622202 01 R.fl?adi ews, by C .M

fliiowney Nov. 6, 1951 B. R. ANDREWS DRYING APPARATUS 2 SHEETS-SHEET 2Filed Dec. 14, 1950 MWWW way I m J Patented Nov. 6, 1951 UNITED STATES TATENT ()FFICE 4 Claims.

This invention relates to drying apparatus for drying web material ofthe type in which said web material to be dried is carried through adrying chamber by a pair of traveling tenter chains, each of which has arow of pins on which an edge of the web is impaled, and the inventionrelates particularly to a drying apparatus of this type in which thedrying is accomplished by directing high velocity jets of heated air orother gaseous drying medium against the web as it travels through thedrying chamber in the manner shown in my United States Patent#2,071,015, February 16, 1937.

One of the dimculties encountered in the operation of a pin tenderdrying apparatus is that sections of the web at one edge or the otheroccasionally become dislodged from the pins while the web is travelingthrough the drying chamber, and if this occurs such sections of the webare nbt held under proper tension and imperfect drying of the web mayresult. One object of this invention is to provide means for overcomingthe above difficulty and insuring that the web will be securely held onthe tenter pins throughout the entire drying operation.

A further object of the invention is to provide a means for holding theweb on the tenter pins by displacing the web downwardly along a narrowzone immediately inside each row of tenter pins.

In drying apparatus such as shown in my said Patent #2,071,015, theheated air which is directed against the web for drying it flows offfrom the web at the edges thereof, and another object of the inventionis to provide a construction by which the downward displacement of theweb along said zones is produced by the flow of the air off from theedges of the web.

In the drawings wherein I have illustrated a selected embodiment of theinvention, Fig. 1 is a cross sectional view through a drying apparatusembodying my invention taken on the line ll, Fig. 2.

Fig. 2 is a fragmentary longitudinal section of a drying apparatusembodying my invention taken on the line 22, Fig. 1.

Fig. 3 is an enlarged fragmentary vertical sec tion through one of thetenter chains and one edge of the web illustrating the manner in whichthe web is displaced downwardly adjacent the tenter chains and therebysecurely held on the tenter pins.

Referring to Fig. 2, which, as stated above, is a longitudinal sectionalview through a part of a drying apparatus of the type shown in my Patent#2,071,015, 2 and 3 represent upper and lower air ducts which aresupplied with heated air under considerable pressure and which formbetween them a drying space 4 through which the web 5 to be dried iscarried by means of tenter chains as will presently be described, saidweb moving in the direction of the arrow as in Fig. 2.

The bottom floor 6 of the upper air duct 2 is formed with a plurality ofnozzles I through which drying medium, such as heated air underpressure, is delivered against the upper face of the web 5, and the topwall or ceiling 8 of the lower air duct 3 is similarly provided with aplurality of nozzles 9 through which the heated air or other dryingmedium is delivered under pressure against the under side of the web 5.

Said nozzles 1 and 9 are preferably in a form to provide slots [0 whichextend transversely across the web 5, with the result that the jets ofair 20 issuing through the nozzles have a sheetlike form. If thesesheet-like jets are delivered against the web at substantially rightangles thereto and at a relatively high velocit they become, uponcontact with the web, converted into whirling cyclonic currents as setforth in said Patent #2,0'71,Q15, which currents finally flow oil? fromthe web at the edges thereof through the open spaces l l between the airducts at both sides thereof.

The web 5 of cloth or other material is supported by and carried throughthe drying space 4 by means of two traveling tenter chains l2, one ateach side of the web 5. The tenter chains are of the pin type, and eachhas a row of pins IS on which an edge of the web is impaled, said chainsbeing supported in their traveling movement by rail assemblies M, asusual in tenter chain devices of this type. Each rail assembly 14includes longitudinally extending track members or guides I1 and 24 bywhich the tenter chain is guided in its movement.

The parts thus far described are such as are commonly found in pintenter chain drying apparatus and form no part of the present invention,which, as stated above, relates to means for maintaining the edges ofthe web 5 securely impaled on the tenter pins l3.

Located above the web at each edge thereof and relatively close theretois a baflle strip 15 which extends longitudinally of the web immediatelyinside of the inner edge of the corresponding tenter chain l2 as bestseen in Fig. 3. Each baflie strip I5 is shown as being mounted on andsupported by a plurality of bracket arms I6 which, in turn, are mountedon the correthe throat I8 along with air which is flowing I over thesurface of the web in contact therewith, as indicated by the arrows ISin Fig. 3. This flow of air against, the baflle strip and downwardlyagainst the web produces an increased pressure on the upper face of theweb 5 along a longitudinally extending zone 2| immediately inside thebaffle strip l5, and said increased pressure tends to displace thematerial of the web in said zone downwardly and thereby the edge of theweb is more firmly held on the tenter pins.

The present invention also provides means whereby the air which isflowing off from the web beneath the latter at the edges thereof createsa reduced pressure beneath the web along said longitudinally extendingzones 2| so that the web in each zone is maintained in its depressedcondition partly by the increased pressure on the upper face of the webalong said zone and partly by the reduced pressure underneath the webalong said zone.

Situated beneath the web 5 at each edge thereof and directly below theupper bafile strip I5, is a lower bafiie strip 22 which has its widthdimension extending horizontally. Each lower baffle strip 22 extendslongitudinally of the web and is secured to the guide or track member 25of the rail assembly by means of suitable hangers 23.

Each lower baflle strip 22 is situated relatively near the lower nozzles9 and has such relation to the web and to the track member 24 that theair current flowing off from the web beneath the latter and which passesthrough the space 25 between the guide member 24 and the lower bafflestrip 22, tends to produce a reduced pressure on the under side of theweb along the zone 2|.

My invention, therefore, provides means whereby the web is subjected tounbalanced pressure pressure on the upper face of the web greater thanon the lower face thereof, and thereby the web along each of said zonestends to be displaced downwardly with the result that the edge the webjets of air which flow off from the web at each edge thereof, thecombination with said tenter chains, each having a row of pins on whicha marginal edge of the web to be dried is impaled, of a bafile stripextending longitudinally of the web at each edge thereof, and meanssupporting each baffie strip above the web immediately inside thecorresponding tenter chain, whereby air flow ing off from the edges ofthe web impinges against and is deflected downwardly by said bafflestrips, thereby producing an increased pressure against the top surfaceof the web along a zone extending longitudinally thereof immediatelyinside of each bafile strip, which increased pressure tends to displacedownwardly the web in each zone and thus more securely hold the edges ofthe web on the tenter pins.

2. A drying apparatus comprising a drying chamber, a pair of pin tenterchains for carrying the web to be dried through said drying chamber,each tenter chain having a row of pins on which the edge of the web isimpaled, means to direct against the under face of the web jets of airwhich flow off from said face at the edges thereof, and meanscooperating with the air thus flowing off from the under face of the webto produce a reduced pressure against the under face of the Web along amarginal zone immediately inside of each row of pins, which reducedpressure is less than that above the web along said zones, suchunbalanced pressure tending to displace downwardly the material of theweb in each zone and thereby more securely hold the Web on the tenterpins.

3. A pin tenter drying apparatus of the type having a drying chamber, apair of pin tenter chains for conveying the web to be dried through saiddrying chamber, and means to direct against both the top and bottomsurfaces of saidweb jets of air which flow off from both surfaces at theedges of the web, the combination with said tenter chains, each having arow of pins on which a marginal edge of the web to be dried is impaled,of a baffle strip extending longitudinally of the web at each edgethereof, means supporting each baflie strip above the web immediatelyinside the corresponding tenter chain, whereby air flowing off from thetop surface of the web along a zone 2| at each edge thereof with the ateach edge thereof lmpmges agamst Sam baffle strips and is deflectedthereby downwardly against the web, thereby producing an increasedpressure against the top surface of the web along a zone extendinglongitudinall thereof immediately inside of each baflie strip, and meansccof the web will be more firmly retained on the tenter pins l3.

It will be understood, of course, that the rail assemblies 14 onopposite sides of the tenter frame are of the type which can be adjustedtoward and from each other to accommodate webs of cloth or othermaterial of different widths, and since the upper and lower baffles aremounted on the rail assemblies, the proper positions of said baiflesrelative to the tenter pins is not disturbed by any adjustment of therail assemblies.

The drawing indicates a single pass tenter, but it will be understoodthat the invention is equally applicable to tenters in which the passesare either of the over and under return type or the multiple pass type.

I claim:

1. In a pin tenter drying apparatus of the type having a drying chamber,a pair of pin tenter chains for conveying the web to be dried throughsaid drying chamber, and means to direct against operating with the airflowing ofi from the under face of the web at each edge thereof toproduce a reduced pressure against the under side of the web along eachof said zones, said increased pressure on the upper face of the web andthe reduced pressure on the under face of the web co-acting to hold moresecurely the edges of the web on the tenter pins.

4. In a pin tenter drying apparatus of the type having a drying chamber,a pair of pin tenter chains for conveying the web to be dried throughsaid chamber, each tenter chain having a row of pins on which a marginaledge of the web to be dried is impaled, a rail assembly for supportingeach tenter chain, a series of upper nozzles to direct against the topface of the web jets of air which flow off from the web at each edgethereof, and a series of lower nozzles to direct against the under faceof the web other jets of air which flow off from said under face at theedges thereof,'the combination with said tenter chains, rail 5 1assemblies and nozzles, of an upper baffie strip extendinglongitudinally of the web at each edge thereof, means supporting eachupper baffle strip above the web immediately inside the correspondingtenter chain, whereby air flowing 01f from the edges of the web impingesagainst said bafile strips and is deflected thereby downwardly againstthe web thus producing an increased pressure against the top surface ofthe web along a zone extending longitudinally thereof immediately insideof each baille strip, a lower baflle strip also extending longitudinallyof the web at each edge thereof, and means supporting each lower bafilestrip below the web relatively near the lower nozzles and spaced fromthe corre- 1 sponding rail assembly, and with its width dimensionextending parallel to the web, whereby the flow of air from the lowernozzles over each 6 lower bafile strip and between the latter and thecorresponding rail assembly produces a reduced pressure on the underface of the web along each of said longitudinal zones, which reducedpressure cooperates with the increased pressure on the upper face of theweb to hold more securely the edges of the web on the tenter chains.

BERNARD R. ANDREWS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,717,004 Buck June 11, 19292,083,141 Buck June 8, 1937 2,083,142 Buck June 8, 1937

